Strain relief connectors for fiber optic cables are common in the connector industry. Conventional strain relief connectors have a sleeve surrounding a light transmitting optical fiber or a plurality of light transmitting optical fibers. The optical fibers are generally surrounded or covered and protected by a jacket or buffer material formed from a plastic. The sleeve and the fiber optic cable are then crimped using a crimping tool into a hexagonal or round shape.
Conventional crimping methods do not allow adequate lateral flow of the jacket material, in other words, the jacket material does not substantially flow in a direction perpendicular to the longitudinal axis of the crimp sleeve. A lack of lateral flow forces the buffer material to flow along the longitudinal axis of the crimp sleeve, producing longitudinal flow. Longitudinal flow places tension on the optical fiber, possibly causing damage to or failure of the optical fiber, or changing its optical characteristics.
In addition, conventional crimping methods have a crimp length that is short relative to the diameter of the jacket material. Generally, the length of the crimp is less than four times the buffer material diameter. This short length results in a small area of frictional contact between the inner surface of the crimp sleeve and the outer surface of the buffer material and may make failure of the connector more likely under tensile or thermal stress.
Furthermore, when assembling and crimping conventional connectors, it can be difficult to properly position the polymer cover within the metal tube or sleeve. Many conventional connectors allow the polymer cover to move longitudinally relative to the sleeve. Also, since the polymer cover is generally disposed within the sleeve, it can be difficult to ascertain the exact location of the polymer cover relative to the sleeve.
Examples of prior art fiber optic cable crimp connectors are disclosed in the following U.S. Pat. No. 3,655,275 to Seagraves; U.S. Pat. No. 4,738,504 to Jones; U.S. Pat. No. 5,140,662 to Kumar; U.S. Pat. No. 5,317,664 to Grabiec et al.; U.S. Pat. No. 5,418,874 to Carlisle et al.; U.S. Pat. No. 5,455,880 to Reid et al.
Thus, a continuing need exists for strain relief fiber optic connectors.